31 years, 3 RVs (first 2 no slide, current 1 two slides); I will never go back to a no-slide RV. The "walk around" room that a slide provides is something I will never consider giving up, it really is that significant. I do agree that the RV must be usable with the slide in; ours blocks only the dresser drawers below the closet, nothing else; the RV is fully usable with the slides in or out.
Although I hear alot of people who "worry" about kitchen connections in slides, I have seldom if ever read reports of actual problems with them. Ours does indeed house the kitchen sink, stove, microwave and dinette (not the fridge), and we have not had a single issue with water lines, drain lines, gas lines, or electrical lines. Since it is now 16 years old, I assume that it would have had issues with those lines by now if it was prone to them. The slide mechanism itself (HWH Hydraulic, both slides and jacks) has also been trouble free, although it does have a way to manually retract them.